A Unilateral Contract is defined as:

• A. When both promise to do something
• B. When only one promises to do something and the other pays option money
• C. An express contract
• D. An informal contract

Answer: (B)

Unilateral contracts hinge on one promise and acceptance through performance. In this setup, only one party commits to doing something, and the contract is activated when the other party actually performs the requested act. The idea of paying option money fits here as the consideration that keeps the offer open or secures the deal, reinforcing that acceptance comes through the other party’s performance rather than through a promise to perform. This is different from a bilateral contract, where both sides promise to do something, and from an express vs informal distinction, which isn’t about whether the agreement is one-sided or two-sided.